According to the Danish study a child is exposed to 120
µg of
DEHP per square cm of
eraser which is in contact with its saliva for an hour (120
µg/cm2/h), but this is likely to be a six-fold overestimate.
This rate of transfer from eraser to saliva is comparable to the
highest DEHP values measured in a US study and ten times higher
than the results for DINP
releases in two European studies. Therefore, in this
risk assessment, the
figure of 120 µg/cm2/h is considered a worst-case scenario. It
is also assumed that 100% of the phthalate in the saliva or in
swallowed particles passes into the body.

The Danish report also assumed that a child sucks on a piece
of eraser for one hour per day, which the
SCHER considered a
reasonable worst case given that most children hardly ever put
an eraser into their mouths.

In the Danish report, the exposure through ingestion of small
solid particles after chewing was calculated for 8, 50 and 100
mg of particles per day. However, practical experiences show
that such bitten-off pieces of eraser are not easily swallowed,
and the SCHER considers
that 8 mg of particles per day is the only realistic value.

Another big unknown, which represents the largest uncertainty
factor in this assessment, is how frequently children bite and
swallow bits of erasers.

With these assumptions, the total exposure to
DEHP from 1 cm2 of an
eraser containing 44% DEHP may be 0.1 mg or up to 4 mg per child
per day depending on whether the child merely licks the eraser
or if particles are bitten off and swallowed. When combining all
worst-case scenarios, exposure to DEHP from chewing erasers
could reach up to 4.1 mg per child per day, which is equivalent
to 0.2 mg/kg body weight per day for a 6 year old child who
weighs 20 kg. This is four times the tolerable daily intake
(TDI) of 0.05 mg/kg body
weight per day. The margin of safety compared to the lowest
level of DEHP at which no adverse effect were observed in
animals (NOAEL) is 25, when
the generally accepted margin of safety is 100 times.

However, licking on erasers and swallowing bits of them is a
short-lived habit and children are unlikely to swallow large
amounts of eraser in this way. The exposure time is short and
phthalates are rapidly
transformed and eliminated from the body. Comparing such worst
case short term exposures with the
TDI, which is meant for
regular, lifetime exposures, is not really appropriate here.
Moreover, the assessment of exposure by swallowing particles
relies on a single exploratory experiment, which needs to be
repeated to confirm the findings. Only very few children in the
groups where DEHP intake
was determined from urine samples
(biomonitoring) exceeded
the TDI.
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